If you go into your local branch of your mum's bank with the certified copy of the POA (and identification - never try any of this without photo ID and proof of yours and her address!) you can set up an arrangement where you can have a duplicate bank card and cheque book for her account so - only if/when you need it - everything is in place. You will also be able to withdraw cash for expenses and arrange for duplicate statements to be sent to you if you want- it's just like running your own account. If you can also arrange on-line access to her account, this will enable you to keep an eye on what she's spending and step in if anything starts seeming odd.
You also should make her bank aware of her dementia problems because there will come a time when she won't remember the PIN no on her debit card and she could be held liable if she has given this to a carer, shopkeeper or anyone else. Or written it on the card
![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
The bank can then decide if/when they need to issue her with a chip and signature card instead. At least if you have formally informed them, that will cover you in case the card is fraudulently used.
It's all about staying one step ahead of the game; the aim is to have the systems in place before you need them.
In the early days, I used to take mum to the shops in a wheelchair when I visited which made a nice outing but these days, I just buy what she needs and reimburse myself from her account. If you buy her something from any of the high street stores, it's easy to change it if it doesn't fit.